The toxic effects of amphetamine and amphetamine-like compounds have been examined in neuronal cell cultures and in a rat in utero model. In culture, amphetamine-like compounds have a toxic effect on both cell survival and replication at micromolar concentrations. These effects were not stereospecific and not mediated by high affinity uptake systems. In utero chronic treatment with methamphetamine had later behavioral effects in adult life and were accompanied by regionally specific changes in brain monoamine levels and uptake systems. These results indicate a developmental susceptibility of certain neuronal populations to the effects of amphetamines.